# Trellis

> A trellis is a net, mesh or frame that supports plants and spreads their branches, either as a SCROG screen or as support for heavy colas in flower.

- Canonical: https://genetixbay.com/knowledge/glossary/trellis.html
- Also written: trellis net, trellis netting, plant netting, support net, scrog screen, yo-yos
- Glossary category: Cultivation and training · Evidence: Grower practice
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

A trellis is a support structure, most often a flexible net with square cells of about 10-15 cm (4-6 in), stretched horizontally over the plants. Indoors it does two jobs: a training screen ([SCROG](https://genetixbay.com/knowledge/glossary/scrog.md)) that spreads [tops](https://genetixbay.com/knowledge/glossary/top-shelf.md) into a [flat canopy](https://genetixbay.com/knowledge/glossary/even-canopy.md), and a support layer that stops heavy [colas](https://genetixbay.com/knowledge/glossary/cola.md) falling over in late flower.

## In practice

Many growers run two layers: the first 20-30 cm (8-12 in) above the medium for training, the second 30-40 cm (12-16 in) higher for support during the [stretch](https://genetixbay.com/knowledge/glossary/stretch.md). The net must be anchored tightly to a frame or tent poles; a sagging net does neither job. Outdoors, vertical nets, cages or stakes do the same work against wind and rain.

Hanging retractable supports ("yo-yos") are used for single heavy branches.

## Don't confuse with

- **SCROG**: the training method; a trellis is the equipment.
- **Stakes and ties**: individual supports rather than a whole-canopy net.

## Related terms

[SCROG](https://genetixbay.com/knowledge/glossary/scrog.md), [Plant ties](https://genetixbay.com/knowledge/glossary/plant-ties.md), [Canopy](https://genetixbay.com/knowledge/glossary/canopy.md), [Tucking](https://genetixbay.com/knowledge/glossary/tucking.md)

## Read more

- [SCROG: screen of green](https://genetixbay.com/knowledge/training/scrog.md)